1-(4-nitrophenyl)-1-(4&#39;-nitrophenyl)-2,2-dihalocyclopropane insecticides



United States Patent 689,317, now Patent No. 3,481,993, dated Sept. 13,

1969. Divided and this application Jan. 30, 1969, Ser.

Int. Cl. A01n 9/20 U.S. or. 424-349 2 Claims ABSTRACT OF THE DISCLOSURECompounds of the formula NOPQCRQmOZ wherein Y is selected from the groupconsisting of chlorine, bromine and fluorine and Y is selected from thegroup consisting of chlorine and bromine provided that when Y isfluorine Y is chlorine, are useful in combating insects.

This application is a division of copending application Ser. No.689,317, filed Dec. 11, 1967 now US. Pat. No. 3,481,993.

This invention provides certain new 1-(4-nitrophenyl)-1-(4'-nitrophenyl)-2,2-dihalocyclopropanes, which possess propertiesuseful for combating insect pests. The invention also provides methodsfor the preparation of said new compounds; the method of combatinginsect pests by utilizing said new compounds; and, insecticidalformulations embodying said new compounds.

The new 1 (4 nitrophenyl)-1-(4'-nitrophenyl)-2,2- dihalocyclopropanes ofthis invention have the formula:

wherein Y is selected from the group consisting of chlorine, bromine andfluorine and Y is selected from the group consisting of chlorine andbromine, provided that when Y is fluorine Y is chlorine. Thus, thecompounds of the above formula which are useful in the compositions andmethods of this invention are:

1-,(4-nitrophenyl) -1- (4'-nitrophenyl) -2,2-

dichlorocyclopropane 1- 4-nitrophenyl) -1- (4'-nitrophenyl) -2,2-

dibromocyclopropane 1 (4-nitr0pheny1) -1- (4-nitrophenyl) -2,2-

chlorobromocyclopropane 1-,( 4-nitrophenyl -1- (4'-nitrophenyl) -2,2-

chlorofluorocyclopropane The new compounds of the invention can beprepared by the nitration of the appropriate 1,1-diphenyl-2,2- dihalocyclopropane, as illustrated by the following equation:

wherein Y and Y are as defined above, it having been found thatnitrosubstitution occurs virtually exclusively in the 4-position of eachphenyl ring, since other isomers were undetected. The usual procedurefor nitration apply except that fuming nitric acid (specific gravityabout 1.5, concentration about 98%) is required for a desirable reactionrate. It is preferred to use a mixture of acetic anhydride and aceticacid as reaction medium. The material to be nitrated preferably is addedslowly to the nitration mixture (nitric acid plus acetic acid/aceticanhydride) and the exothermic reaction is controlled by cooling.Preferably, the reaction is maintained at room temperature or below, thebest conditions being about -5 to -|-10 C. Time of reaction is governedby the ability to cool the reaction. After addition is complete, themixture should be stirred for a suitable minimum period, say 15 to 30mins. The desired compound is isolated by quenching the reaction mixtureinto water or ice and filtering, the end product being purified ifnecessary by recrystallization.

The following non-limitative example illustrates the preparation of thenew compounds of the invention:

EXAMPLE 1 Fuming nitric acid (8.6. 1.5; 13 ml.) was added dropwise to amixture of glacial acetic acid (12 ml.) and acetic anhydride (20 ml.),keeping the temperature below 10 C. To this was added in small portions1,1-diphenyl- 2,2-dichloro cyclopropane (11.2 g.) with stirring andcooling. The addition took 1 hour, the temperature of the reactionmixture being maintained between 5 and +5 C. It was stirred for 15minutes and quenched into 200 ml. of iced water. The product, 1,1-bis(p-nitrophenyl)-2,2-dichlorocyclopropane, was separated by filtration,washed with diluted nitric acid, and recrystallized from ethanol. Yieldof product, M.P. 184 C. was

1,1-diphenyl-2,2-dihalo cyclopropane starting materials employed abovecan be obtained by a number of methods involving reaction of anappropriate 1,1-di-phenyl ethylene having the structural formula:

such as phenyl,(trichloromethyl)mercury or phenyl(bromodichloromethyl)mercury or phenyl(tribro'momethyl)mercury orphenyl(dibromochloromethyl)mercury. The two'reaction components can bemixed in any manner in an aprotic solvent and heated. Preferably,benzene is used as the solvent but other solvents such as chlorobenzene,dimethyloxyethane, sulpholane, dimethylformamide, and the like, may beused. The temperature varies with the solvent, which should preferablyboil above 50 C. The reaction is continued until substantially complete,this being usually about two hours, but longer periods are notdeleterious. Phenylmercuric chloride or bromide is obtained asby-product, and can be removed by filtration. The desired end productmay be isolated by conventional means such as evaporation andfiltration. Yields of almost 100% can be obtained.

An illustrative practical example for the preparation of1,1-diphenyl-2,2-dichlorocyclopropane by the method indicated above isas follows:

EXAMPLE 2 1,1-diphenyl ethylene (18 g.) was refluxed with a solution ofphenyl(trichloromethyl)mercury (40 g.) in chlorobenzene 700 ml. for 4hours. The mixture was cooled and the precipitated phenylmercuricchloride was filtered off. The solvent was distilled from the filtrateand the residual product was recrystallized from petroleum ether to givea 96% yield of crystals melting at 114 C.

An alternative procedure for the preparation of the 1,1-diphenyl-2,2-dihalocyclopropane starting materials involves reaction ofthe appropriate 1,1-diphenylethylene with a 'haloform and a base. Thehaloform may be chloroform or bromoform or bromodichloromethane ordibromochloromethane or dichlorofluoromethane, while the base preferablyis potassium tert-butoxide, however, other bases such as butyl lithium,methyl lithium, and sodium hydroxide pellets may be used. Otheralternative procedures involving systems which generate dihalocarbenewhich can be used are the reaction of ethyl trichloroacetate and sodiummethoxide; or the decarboxylation of sodium trichloroacetate; or thereaction of hexachloroacetone and a base, in each case the appropriate1,1-diphenylethylene being included in the reaction system.

Appropriate 1,1-di-(p-substituted phenyl)ethylene starting materials canbe prepared by known methods such as from p-substituted phenyl magnesiumbromide and ethyl acetate; or from methyl magnesium iodide and4,4'-disubstituted benzophenone followed by dehydration; or fromsubstituted acetophenone, as noted in Organic Syntheses CollectiveVolumes I, pp. 221-222, 1932 edition.

Compounds of Formula I, hereinafter referred to as active compounds, inaccordance with the invention are useful in the combatting of insectpests, particularly DDT- resistant insect pests such as DDT-resistantmosquitoes and flies and their larvae, as well as in the combatting ofother insect pests in general, such as Southern Army worm, ashereinafter indicated. It is surmised that an inability of insect lifeto effect dehydrochlorination of the above specified active compounds isresponsible for the unique activity of the active compounds againstinsect pests which have become DDT-resistant. Besides possessing theunique insecticidal activity indicated, it has been established that theactive compounds also have a very low level of toxicity towards animalsand a wide range of economic plants.

In combatting insect pests according to the invention, any of the activecompounds either per se or insecticidal compositions comprising one ormore of said active compounds are applied to the insect pests or totheir environment in a lethal or toxic amount. This can be done bydistributing the active compounds or an insecticidal compositioncomprising them in or about an infested environment or in or about anenvironment which the insect pests frequent, e.g. agricultural soil orother growth media or other media attractable to the pests forhabitational or sustenance or propagational purposes, in anyconventional fashion which permits the insect pests to be subject to theinsecticidal action of the active compounds. Such distribution can bebrought about by applying sprays or particulate solid compositions to asurface infested with the insect pests or attractable to the pests, asfor example, the surface of an agricultural soil or other habitat mediasuch as the above-ground surface of host plants by any of theconventional methods, e.g. power dusters, boom and hand sprayers, andspray dusters. Also for sub-surface application such distribution can becarried out by simply mixing the active compounds per se or insecticidalspray or particulate solid composition comprising same with the infestedenvironment or with the environment the insect pests frequent, or byemploying a liquid carrier for the active compounds to accomplishsub-surface penetration and impregnation therein.

Thus, although the active compounds are useful per se in combattinginsect pests, it is preferable in practising the method of the presentinvention, that the active compounds be applied to the pests or to theenvironment of the pests in a dispersed form in a suitable extendingagent. In this specification the term dispersed is used in its widestpossible sense, thus, the term means that particles of the activecompounds may be molecular in size and held in true solution in asuitable organic solvent; the term also means that the particles may becolloidal in size and distributed throughout a liquid phase in the formof suspensions or emulsions or in the form of particles held insuspension by surface-active agents of a non-ionizing character; theterm also means that the particles can be distributed in a semi-solidviscous carrier such as petroleum or other ointment base of anon-ionizing character in which they may be actually dissolved in thesemi-solid or held in suspension in the semi-solid with the aid ofsuitable non-ionizing surface-active agents; the term also means thatthe particles may be mixed with and distributed throughout a solidcarrier providing a mixture in particulate form, e.g. pellets, granules,powders, or

dusts; and the term also means that the particles can be in mixtureswhich are suitable for use as aerosols including solutions, suspensions,or emulsions of the active compounds in a carrier such asdichlorodifluoromethane and like fluorochloroalkanes or mixtures ofthese and/or with other substances which boil below room temperature atatmospheric pressure. In this specification and appended claims, theexpression extending agent includes any and all of those substances inwhich the active compounds are dispersed, including, therefore, thesolvents of a true solution, the liquid phase of suspensions, emulsionsor aerosols, the semi-solid carrier of ointments, and the solid phase ofparticulate solids, e.g. pellets, granules, dusts and powders.

The concentration of the active compounds employed according to theinvention in combatting insect pests can vary considerably provided therequired dosage (i.e. toxic or lethal amount) thereof is supplied to thepests or to the environment of the pests. When the extending agent is aliquid or mixture of liquids as in solutions, suspensions, emulsions, oraerosols, the concentration of the active compound employed to supplythe desired dosage generally will be in the range of 0.001 to 50 percentby weight. When the extending agent is a semi-solid or solid, theconcentration of the active compounds employed to supply the desireddosage generally will be in the range of 0.01 to 25 percent by weight.

There are a large number of organic liquids which can be used for thepreparation of solutions, suspensions or emulsions of the activecompounds. For example, isopropyl ether, acetone, methyl ethyl ketone,octanone, dioxane, cyclohexanone, carbon tetrachloride, ethylenedichloride, tetrachloroethane, hexane, heptane, and like higher liquidalkanes, hydrogenated naphthalenes, solvent naphtha, benzene, toluene,xylene, petroleum fractions (e.g. those boiling almost entirely under400 F., and having a flash point above about F., particularly kerosene),mineral oils having an unsulfonatable residue above about 80 percent andpreferably above about 90 percent. In those instances wherein there maybe concern about the phytotoxicity of the organic liquid extendingagent, a. portion of same can be replaced by such low molecular weightaliphatic hydrocarbons as dipentene, diisobutylene, propylene trimer,and the liker or suitable polar organic liquids such as the aliphaticethers and the aliphatic ketones containing not more than about carbonatoms as exemplified by acetone, methyl ethyl ketone, diisobutyl ketone,dioxane, isopropyl ether, and the like. In certain instances, it isadvantageous to employ a mixture of organic liquids as the extendingagent, e.g. an aromatic hydrocarbon and an aliphatic ketone.

When the active compounds are to be supplied to the insect pests or tothe environment of the pests as aerosols, it is convenient to dissolvesaid compounds in a suitable solvent and disperse the resulting solutionin dichlorodifluoromethane or like chlorofiuoroalkane or mixtures ofthese or with other aerosol dispersants which boil below roomtemperature at atmospheric pressure. In this connection the inventionprovides as a new article of manufacture, suitable for combatting flyinginsects, particularly DDT-resistant mosquitoes, in and around thehousehold, an aerosol pressure-pack comprising a pressurized containerenclosing an aerosol composition embodying said active compounds.

The active compounds are preferably applied to the insect pests or tothe environment of the insect pests in the form of emulsions orsuspensions. Emulsions or suspensions are prepared by dispersing thesaid active compounds either per se or in the form of an organicsolution thereof in water with the aid of a water-soluble non-ionicsurfactant. The term surfactant as employed in this specification isused as in Volume II of Schwartz, Perry and Berchs Surface Active Agentsand Detergents (1958, Interscience Publishers, Inc., New York) in placeof the expression emulsifying agent," to connote generically the variousemulsifying agents, dispersing agents, wetting agents and spreadingagents that are adapted to be admixed with the said active compounds inorder to secure better wetting and spreading of the active compounds inthe water vehicle or carrier in which the said active compounds areinsoluble through lowering the surface tension of the water (see alsoFrear Chemistry of Insecticides, Fungicides and Herbicides, secondedition, page 280). The surfactants contemplated are the wellknowncapillary active substances which are non-ionizing (or non-ionic) andwhich are described in detail in Volumes I and II and Schwartz, Perryand Berchs Surface Active Agents and Detergents (1958, IntersciencePublishers, Inc., New York), and also in the November 1947 issue ofChemical Industries (pages 811-824) in an article entitled SyntheticDetergents by John W. McCutcheon and also in the July, August, Septemberand October, 1952 issues of Soap and Sanitary Chemicals under the titleSynthetic Detergents. The disclosures of these articles with respect tonon-ionizing capillary active substances are incorporated in thisspecification by reference in order to avoid unnecessary enlargement ofthis specification. The preferred surfactants are the water-solublenonionic surface-active agents set forth in US. Pat. No. 2,846,398.

The active compounds can be dispersed by suitable procedures (e.g.tumbling or grinding) in solid extending agents either of organic orinorganic nature and applied to the insect pests environment inparticulate form. Such solid materials include for example, tricalciumphosphate, calcium carbonate, kaolin, bole, kieselguhr, talc, bentonite,charcoal, fullers earth, pyrophillite, diatomaceous earth, calcinedmagnesia, volcanic ash, sulfur and the like inorganic solid materials,and include for example, such materials of organic nature as powderedcork, powdered wood, and powdered walnut shells. The preferred solidcarriers are the adsorbent clays, e.g. bentonite. These mixtures can beused for insecticidal purposes in the dry form, or by addition ofwater-soluble nonionic surfactants the dry particulate solids can berendered wettable by water so as to obtain stable aqueous dispersions orsuspensions suitable for use as sprays. For special purposes the activecompounds can be dispersed in a semi-solid extending agent such aspetrolatum with or without the aid of solubility promotors and/ ornon-ionic surfactants.

A concentrate, for example in the form of a spray base or particulatesolid base may be provided in such form that, by merely mixing withwater or with a solid extender (e.g. powdered clay or talc) or otherlow-cost readilyavailable material, an easily prepared spray orparticulate solid insecticide for household or agricultural purpose canbe produced. In such a concentrate composition, the above activecompounds generally will be present in a concentration of 5 to percentby weight, the residue being any one or more of the well-knowninsecticidal adjuvants, such as the surface-active clays, solvents,diluents, carrier media, adhesives, spreading agents, humectants, andthe like.

A particularly useful concentrate ready for mixing with or dispersing inother extending agents is an intimate mixture of the active compoundswith a wetting and dispersing agent in a proportion of 0.1 to 20 partsof surfactant with suflicient of the active compounds to make parts byweight. Such a concentrate is particularly adapted to be made into aspray for combatting various forms of insect pests by the addition ofwater thereto. As illustrative of such a concentrate is an intimatemixture of 20 parts by weight ofl-(4-nitrophenyl)-l-(4'-nitrophenyl)-2,2-dichlorocyclopropane and 5parts by weight of a wetting and dispersing agent. Another usefulconcentrate adapted to be made into a spray for combatting insect pestsis a solution (preferably as concentrated as possible) of the activecompounds in an organic solvent containing a minor amount (e.g. 0.5 to15 percent by weight of the weight of the active compounds) of anemulsifying agent. As illustrative of such a concentrate is a solutionof 1-(4-nitrophenyl)-1-(4'-nitrophenyl)-2,2-dichlorocyclopropane insolvent naphtha, xylene or a pctroleum fraction such as kerosene,containing an emulsifying agent.

In all of the various dispersions described hereinbefore forinsecticidal purposes, the said active compounds can be advantageouslyemployed in combination with other pesticides, including for example,other insecticides, nematocides, bactericides, and herbicides. In thismanner it is possible to obtain mixtures which are effective against awide variety of pests and other forms of noxious life.

Insecticidal activity of the new compounds of Formula 1 above wasdemonstrated in tests against mosquito larvae specie Aedes aegypti, ofthe family Culicidae of the order Diptera, as follows:

Aedes aegypti; A rimless, 25 x 200 culture tube was rinsed with acetoneand was placed in a holding block. The tube was filled with 70 cc. ofdistilled Water, and 0.1 cc. of liquid or 0.1 g. of the solid testcompound was dissolved in acetone to make a 1% by-Weight concentrate ofthe test chemical, 0.007 ml. of this concentrate was pipetted into theculture tube containing the distilled water. The tube was then stopperedwith an acetone washed rubber stopper and shaken to facilitate completemixing. Approximately 25 early fourth instar yellow fever mosquitolarvae Aedes aegypti were transferred to the tube with the aid of apipette. The larvae were held in the test tube at room temperature for24 hours at which time mortality observations were taken. Any larvaecapable of any movement was considered to be alive. Under test 1,1dichloro 2,2-bis-(p-nitrophenyl)-cyclopropane gave 100% kill at aconcentration as low as 0.2 ppm.

While the invention has been described in considerable detail withreference to specific embodiments thereof, other modifications andvariations will suggest themselves to those skilled in the art.

7 The embodiments of the invention, in which an exclusive property orprivilege is claimed, are defined as follows:

1. A method of combatting insects which comprises applying to saidinsects an insecticidal amount of a compound of the formula wherein Y isselected from the group consisting of chlorine, bromine, fluorine and Yis selected from the group 8 consisting of chlorine and bromine providedthat when Y is fluorine Y is chlorine.

2. A method in accordance with claim 1 wherein the compound is1-(4-nitropheny1)-1-(4-nitrophenyl)-2,2-dichlorocyclopropane.

References Cited UNITED STATES PATENTS 11/1966 Wiles 424-354 OTHERREFERENCES Chemical Abstracts 43: 9042b (1949).

JEROME D. GOLDBERG, Primary Examiner

